Spewing Hate But Seeming Like Actors
Clyde Haberman NYC column on hatemongering and threats by Khallid Abdul Muhammad, and standoff with New York City Mayor Giuliani over permit for 1999 Million Youth March; says despite Muhammad's obvious media posturing, there are real public safety issues; says boycott supported by black leaders like Repr Charles B Rangel would allow Muhammad to exercise his freedom of speech and the people of Harlem their right to ignore him (M)